JPS62158597A - Manufacture of multicomponent system congruent melting solder material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides a method for coating a molded part consisting of a first component of a solder material with one or more other components, so that the solder material is particularly brittle during the brazing process. The present invention relates to a method for producing a multi-component conformally fusible braze material by transitioning into a homogeneous phase of eutectic composition with the intermetallic phase components of the present invention. The molded part may be a braze sheet or a braze wire, or one of the two parts to be brazed.

[Conventional technology]

Composite materials are gradually gaining importance in many scientific and technological fields. The brazing industry occupies one important position. In particular, a large number of conformally fusible alloys, especially eutectic alloys, are used as brazing materials. For example, tin-based soft solders or silver-based hard solders can be produced melt-metallurgically and shaped into the desired shape by forming, but this procedure does not require a eutectic composition containing brittle intermetallic phases. In the case of other brazing materials it is generally (= impossible. Examples of such brazing materials are those based on high melting point transition metals such as titanium, zirconium, molybdenum and tungsten. According to the state of the art, in the field of high-temperature brazing, solders are mostly soldered using single-component solders (noble metals such as titanium, zirconium, platinum and rhodium).

Attempts have been made to produce brittle eutectic solder materials made in conventional proportions as formable wires and sheets. For example, during its production, the heel melt, in which the brazing material is present in a eutectic composition state, is rapidly cooled to form a metallic glass state, and molded in this state. However, this method is expensive, and currently only a few cm
A wax sheet with width dimensions of only . For example, this type of wax sheet is covered by West German Patent No. 2755435.
and US Pat. No. 3,856,513.

A known method for applying a multicomponent solder material to a surface to be soldered consists in applying the solder material to the surface to be soldered in such a way that each component is spatially juxtaposed. For example, in West German Patent Application No. 3321438, a heterogeneous phase,
A solder is described which is applied to the surface to be brazed with various overlapping powder molds.

According to this, a multi-component brazing material can also be applied to the surface to be brazed in the form of laminated thin plates each consisting of one component. Even when a solder material consisting of several locally separated components has an overall eutectic composition, in order to melt the solder, the temperature must first be adjusted to at least the melting point. Low (near the melting temperature of the ingredients):
This temperature is by definition C: above the eutectic temperature, in many cases well above it, ie above the solidification temperature of the eutectic mixture. Furthermore, melting actually occurs at different locations on the wax surface and at different times. However, in order to braze parts, the solder dimensions must be kept within acceptable limits by keeping the temperature as low as possible and the brazing time as short as possible to avoid the drawbacks of changing the material and dimensions of the parts; It is generally important to ensure simultaneous melting across the entire brazing surface.

What if temperatures well above the eutectic temperature are required to cause melting? During abrasion, primary mixed crystals are significantly generated in the solder material, and its mechanical properties are significantly deteriorated due to embrittlement. The use of coated solder materials for joining two molded parts is often abandoned.

In West German Patent Application No. 2540755,
A method is described for brazing two parts made of a zirconium alloy by applying a metal mold to one of the parts. In this case, the coating, together with the zirconium alloy, is heated appropriately to form a melt having a eutectic composition. Finally, various processing steps produce a solder joint between the two zirconium parts to be joined. The problem with this method is that the zirconium alloy of one of the parts to be joined is α
phase to the unacceptable β phase. Furthermore, the above-mentioned publication does not contain any description regarding the production of wax. Therefore, the specification of the above-mentioned method suggests that the claimed process steps for joining the parts may or do result in certain benefits starting from the actual brazing temperature. Nothing can be done on the child side (other than avoiding the occurrence of the β phase).

[Problem that the invention seeks to solve]

It is an object of the present invention to provide a method for achieving consistent meltability at the eutectic temperature, even though correspondingly homogeneous solder materials of eutectic composition cannot be processed into dimensions customary for solders due to brittle intermetallic phase components. The object of the present invention is to produce waxes consisting of the components in commercially available shapes and dimensions.

This method should not have the above limitations in fusion metallurgy methods. Furthermore, this method should not have the above-mentioned disadvantages that occur when the solder components are unstably bonded to one another. Furthermore, the aim is to make it possible to solder parts with eutectic solder materials with complexly shaped soldering surfaces in the respective fields of application.

[Means for solving problems]

According to the invention, the object is to charge the molded part into a corrugating device and, in the 'il treatment process, use known means specific to the respective coating treatment to remove the 5 surfaces that may have adhered to it. After removing the oxide film and/or dirt, in a second treatment step the molded part is coated with one or more components of the pond, and in the last treatment step all the components are brought to a eutectic temperature in the boundary zone of the coated molded part. Mixing mechanically and/or by diffusion at a lower temperature to maintain the mixture in the boundary zone at or near a eutectic composition, thereby delaying the mixture at a temperature just below the waxy material's eutectic temperature. This is achieved by melting without melting.

[Effect]

Surprisingly, the method of the present invention shows that even when the brazing component is applied in layers, the brazing component (
A two-phase state can be obtained within the wax, which allows the melting of the wax at the eutectic temperature and, as has been common in the past, at or near the melting temperature of the lowest melting component of the wax material. It doesn't melt for the first time. This melting temperature is generally well above the eutectic temperature.

In this case, to obtain a boundary layer of eutectic composition, essentially any narrow region between the two separately present components A and B is sufficient, and within this region the element A The continuous concentration gradient for atoms of is from O to 100 Ti (this is also true for atoms of element B). The melt that forms within the boundary when the eutectic temperature is reached rapidly expands the melting region due to the high exchangeability of the atoms provided therein, so that the solder material given the overall eutectic composition , it melts congruently under actual brazing conditions at a temperature slightly above the eutectic temperature.

The practical implementation of the invention therefore includes all known methods and methods of coating and bonding techniques that allow components A and B to be tightly bonded in the above-mentioned gradual transition for additional coating in a suitable process step. done by the device. At the same time, this method removes surface contaminants, oxide films and corrosion products from the surface of the components to be coated, or removes these layered deposits on the surface until a thorough mixing of components A and B is achieved, at least for each component. It is necessary to eliminate it to the extent that it can occur at the main part of the interface between them.

When brazing with a solder material constructed in this way, a very fine-grained eutectic structure with minimal primary mixed crystal formation and thus good hardness properties can be obtained.

Crucial to the formation of this structure is to avoid overheating the wax and thus ensure that the co-temperature is transferred at a sufficient rate. After switching off the heat source, the temperature drops almost exponentially. The closer the cooling process is performed to the upper eutectic temperature, the more rapidly the critical temperature range shifts to the eutectic temperature under roughly the same processing conditions, and the supercooling effect of the melt that produces fine granular mixed crystals becomes more pronounced. appear.

As a method that particularly satisfies this condition to a high degree, there is a plasma steam/water separation method (CPVD method). The ion Breaifug method and the high-performance sputtering method with substrate bias belonging to this group allow the coating according to the invention of layers of arbitrary layer materials at relatively low temperatures (up to several 100° C.).

At the start of coating, adhering impurities are removed from the surface by means of ion bombardment), forming a mixing zone of components A and B of the eutectic solder material in the boundary area between the support material and the layer material.

Then, when the eutectic temperature is reached during heating during the brazing process, the same area of the transition zone with eutectic composition melts without any actual delay. At both the solid/liquid phase boundary, at a certain brazing temperature, which can be selected in practice from about 10° C. to just above the eutectic temperature, the other portion of the solid material component melts. A high exchange of material within the melt results in a eutectic composition. The melting process ends when a zero degree equilibrium in the melt occurs depending on the state diadem. The wax sheet present in a thickness corresponding to the co-composition melts completely.

The PVD method described above offers significant advantages over other coating methods such as vacuum evaporation or electroplating. In other words, dirt can be removed by applying ions to the surface of the components present in a solid state in the coating equipment immediately before the start of coating, resulting in a surface free of dirt and oxides that can be used in the next step. The components can be completely mixed in the boundary zone.

When using the CVD method, the formation of the boundary zone between the solid component A and the coating material B takes place due to the high processing temperature and by thermal diffusion. In this case, impurities and oxides on the surface, if it consists of a particular material (:), can be removed by prior annealing in a stream of H1. Typical processing temperatures are according to the state of the art - 600 °C - 1100℃
However, this must be chosen in such a way that the eutectic temperature is not reached in all cases.

The present invention can also be practiced with Rollerplay 1 ink. Of course, additional environmental conditions arise in this case due to the need to match the mechanical properties of the solder components to one another. Roller brating (2) The surfaces to be bonded should be freed from deposits, oxide films and the like by means of suitable mechanical and chemical pre-treatments as soon as possible before roller blasting. Treated in air. In general (: the rapidly regenerating thin oxide film is removed by forming the material during a-lar brating under critical conditions known in pressure or friction welding of metals, and cold welding of materials A and B) Once again a mixed transition zone can be formed on a microscopic scale.

Rolling can be carried out at room temperature or at elevated temperature, depending on the materials used. In the case of cold-rollable thin plates, the temperature is lower than the eutectic temperature TE (for example, 05 to 0.7 T).
By thermal diffusion by a subsequent sintering treatment at , the required concentration gradient can be obtained over the entire interface, which makes the melt state suitable for forging.

A coating method in which all of the solder components are not mixed in the boundary layer can also be used to produce the eutectic solder according to the present invention, but this is because the diffusion of each component is thermally activated by the heat treatment performed after coating. Assuming that.

Although this is possible in principle in the case of vacuum-deposited and electroplated coatings, for example, it is rarely realizable.

In the method of the present invention, the first component of the solder material is a thin plate;
It is particularly suitable for producing all eutectic solder materials, on which one or a mixture of several metal components has been applied in accordance with the inventive method. By matching the thickness of the laminates and the applied layers, the material composition of the solder material as a whole corresponds to the proportion of the individual metal components in the corresponding eutectic mixture? Maintaining is achieved. When brazing with solder sheets of this type, the entire solder material with a eutectic composition melts in the shortest possible time when the eutectic temperature is exceeded, and upon subsequent cooling it crystallizes in a eutectic structure.

In the case of commercially available solder sheets with a thickness Q, ] w, the layer thickness to be applied is often 10, depending on the composition of the eutectic mixture.
It is less than 0μ. If the thicknesses of components A and B differ significantly, the thinner layer is generally applied as a coating onto the thicker component, which serves as a supporting lamina. Layer thicknesses of up to a few 100 μm can be applied economically by PVD and CVD methods belonging to the state of the art and by roller plating methods.

The quality of the solder joints produced with the solder material according to the invention does not differ from the quality already obtained with previously produced solders of eutectic composition and structure.

Depending on the level of coating technology, it is possible to apply the coating material B to one or both sides of the support material A. This increases the shape stability of the composite during heating. Depending on the processing technology, double-sided coatings can be applied easily, especially by roller blasting. It is also technically possible to coat with one or more layer materials to produce ternary eutectic mixtures (or quaternary systems, etc.).

Depending on the state of the art, many coating methods can be applied for continuously coating strips or wires. For example, strips up to 1 to 2 m wide can be coated by the unwinding method. If there are significant limitations due to the particular type of coating equipment, it is also possible, within certain limits, to subsequently roll the solder material according to the invention into a solder sheet to a desired thickness (initially on a small surface, but , the thickness gradually increases)
.

This method is an excellent choice for joining two molded parts with complexly shaped brazing surfaces. If the brazing surface is not perfectly flat.

It is well known that it is extremely difficult to uniformly apply a brazing sheet to one side of the workpiece to be brazed and to produce a brazing treatment of uniform thickness over the entire brazing surface. What does this mean?A molded part consisting of a first component of Naruwa material is coated with one or more other components using various coating techniques? , with a sufficiently uniform but predefinable layer thickness in all cases depending on the coating method in each case, to avoid the disadvantages mentioned in the soldering sheet of the first part with the second molded part. It can be brazed at the same time. During the brazing process 1, eutectic melting occurs within the boundary 1v between the molded part and the applied solder component.

Then the entire brazed surface (=
Over time, the melting of the applied wax component proceeds while simultaneously melting all the materials of the molded part. The eutectic composition of the melt is always maintained. This achieves a uniform, predetermined distribution of the molded part (often in the range of less than 0.01 mm), a sufficiently uniform distribution of the solder thickness and overall low tolerances of the molded part composite.

As mentioned at the outset, high-temperature solders in particular have become increasingly important in recent years when joining molded parts made of high-melting point workpieces, especially transition metals, by brazing.

In this case, the advantages of the eutectic solder material according to the invention are particularly outstanding with regard to its application compared to the single-component solders that have been used to date. The process according to the invention is particularly applicable to the transition metals T1°Zr, Hf, V, Nb, Ta, Cr, Mo and W in mutual combination or the noble metals Age Au,
Ru.

Rh, Pd, Os, Ir, Pt or iron group metal Fe
, Ni and Co in combination with one or more of Co, Ni and Co.

Table 1 at the end exemplifies several solder materials of this type with their respective eutectic compositions and eutectic temperatures. For comparison, the melting points of each main component of the wax are also listed.
Write down. The processing technology advantages of eutectic solders are clear even from the respective temperature differences, which in the example described are up to 350°C (2). When brazing other workpieces to be soldered, these solders are significantly expanded in terms of solder material and brazing temperature than currently available solder materials.

One composition of the eutectic solder consisting of high melting point transition metals is Zr.
0.7 +, Mo 2 O,29 laminar solder materials are particularly useful for joining molded parts made of molybdenum or molybdenum alloys with each other or with graphite.

〔Example〕

Next, a practical embodiment of the method of the present invention will be explained in detail based on an example.

Example 1 A thin zirconium plate with a thickness of Q, ]w and a size of 500 x 200- is placed in a PVD ion blating device.
The thin plate is stretched flat and mounted so as to be cathodically connected to the wall of the vacuum chamber. In a vacuum chamber? First, high vacuum (
p is smaller than 10 Pa), and a high voltage of several kV is applied to the zirconium thin plate under an argon pressure of IPa to generate a glow discharge. During the glow discharge, the zirconium sheet is removed by ion bombardment (decontamination) from surface contamination and any oxide layer that may occur. Next, all molybdenum ions are plated onto the zirconium thin plate by electron beam evaporation of molybdenum from a cold water type sM4 while continuing glow discharge. Molybdenum*m is applied until the layer 1527μ is thick, so that the zirconium/molybdenum composite sufficiently approaches the state of eutectic composition.

The thus-wrapped sheet can be bent 180 degrees at a radius of 1 square inch without breaking the coating diameter. The adhesion of the layers is excellent and no cracks appear on bending. The structure of the larvae is nonporous and minutely rod-shaped. An alloying transition with a width of about 50 nm in the transition zone between the substrate and the coating could be confirmed by Auger electron microscopy.

Molded parts made of molybdenum and molded parts made of graphite, and graphite again? This wax sheet was used to braze with graphite. According to literature, the eutectic temperature of molybdenum/zirconium alloy is 1510°~
The temperature is 1520°C. In this brazing experiment, the braze material was brought to a temperature of 1530°C at a high heating rate (approximately 50°C per minute).

When the brazing temperature was reached, heating was stopped and the vacuum chamber was completely filled with helium for rapid cooling. The total residence time of this brazing material at temperatures above the eutectic temperature was less than 1 minute with this procedure.

Metallurgical examination of the brazed layer revealed that the sheet was completely melted and the solder solidified in a microcrystalline eutectic structure. The achieved mechanical stability of the solder joint with respect to moisture and tensile, shear and bending stresses (-) on the surface of the parts to be brazed also exceeded the values obtained when using pure metal solders. .

Example 2 A thin-walled molybdenum tube was coated with rhodium (layer thickness 25 μm) in the area of the intended brazing area using an ion sprayer. When brazing the tube into the borehole, the solder was coated with rhodium (layer thickness 25 μm). Melt at 1940°C.

In order to form a eutectic melt, the tube wall is uniformly and thoroughly alloyed. Locally strong aggressive effects on the wall of the molybdenum tube, which occur in conventional brazing processes with the same rhodium wire, could be completely avoided.

Example 3 Roller-blating a eutectic molybdenum/nickel solder into a symmetrical sheet pack of nickel/molybdenum/nickel in overall stoichiometric proportions: nickel 15μ, molybdenum 100μ, nickel 15μ Manufactured by. This sheet pack was heated and rolled at a temperature of approximately 1000°C in a sealed state.Diffusion under pressure produced an excellent bond between the nickel sheet and molybdenum, and at the same time created the concentration gradient necessary for eutectic melting. The thus obtained 0.1 fin brazing seam 1.
Molded parts made of molybdenum] It was used for brazing at a brazing temperature of 350°C. In this case too, the melting process was virtually undelayed and occurred simultaneously at all locations at approximately 1320°C.

Military day below De゛・　1　.

Table 1: Eutectic high-temperature brazing components in brittle intermetallic phases Eutectic temperature ('C) Melting temperature of main component (-C,)Zr-Mo'' ]520
1850 Blood-Mo 1320
1450 Tt +408
]]875Zr-Re 159
3 1850 knee Ru 16
] 0 + 875Zr-W
+795 1850 and 9-Mo 194o +9
66Ru-Mo 1945
2500Zr-(W/Mo1 1520~+795
1850≠ The main components of wax are underlined.

Claims (1)

[Scope of Claims] 1) A molded part consisting of a first component of a brazing material with one or several other components, such that the brazing material is formed into a particularly brittle intermetallic phase component and a homogeneous phase of eutectic composition during the brazing process. In a method for producing a multi-component conformally meltable solder material by coating such that a first
In the treatment step, any oxidized film and/or dirt that may have adhered to the surface is removed by known means specific to the respective coating treatment, and in a second treatment step the molded part is coated with one or more other coatings. and in the boundary zone of the coated molded part in the last processing step, all the components are mixed mechanically and/or by diffusion at a temperature below the eutectic temperature, so that the mixture in the boundary zone has a eutectic composition. or a method for producing a multicomponent concordantly melting solder material, characterized in that it maintains an approximately eutectic composition, thereby causing the entire solder material to melt without delay at a temperature just above the eutectic temperature. 2) A method for producing a brazing material according to claim 1, characterized in that the coating is carried out by an ion plating method, and each component is mixed within a boundary region by ion bombardment. 3) A method for producing a solder material according to claim 1, characterized in that the coating is carried out using a high-performance sputtering device at different potentials between the supply source and the body to be coated. 4) A method for producing a brazing material according to claim 1, characterized in that the coating is carried out by chemical vapor deposition (CVD) while forming interdiffusion regions within the surface area. 5) One of the two molded parts to be joined to each other, in particular a molded part with a complexly shaped brazing surface, is made of a material corresponding to the first component of the brazing material, and one or more of the first components are 5. A method for producing a brazing material according to claim 1, characterized in that the brazing material is coated with other components of the seed. 6) Transition metals Ti, Zr, Hf,
V, Nb, Ta, Cr, Mo and W may be mutually used, or one or more of these metals may be substituted with the noble metals Ag, Au,
Claims 1 to 5 characterized in that they are used together with one or more of Ru, Rh, Pd, Os, Ir and/or pt and/or iron group metals Fe, Ni and Co. A method for producing a brazing material according to any one of the above. 7) The first component of the brazing material is zirconium, and the second component is zirconium.
6. The method for producing a brazing material according to claim 1, wherein the component is molybdenum, and the weight ratio of both components is 71/29. 8) Claim 1, characterized in that the first component of the braze material is a thin free-standing, extensible sheet, and the amount of all components within the braze material corresponds to the total amount of the eutectic composition. The method for producing a brazing material according to any one of Items 4 to 4, 6, and 7.